His name is the Demolisher. He doesn't ignore the spikes. He goes through them like they are twigs and they get....demolished.

The code for him literally reads: "stompspikes true"

Remember that this is a late game enemy. Your spikes will be useful for a large portion of the game. The point of the demolishers is to prioritize them and take them out while they are still distant. If you let them get close then your defenses and your base will take damage as he moves through and then even more damage if he explodes.

Interestingly, there is no code for stomping barbedwire....

Demos destroy spike and barbed wire blocks on contact. They do take a hit from the spike or barbed wire, so it does slow them a bit.